KDP spine width calculator and cover size
Free: type your page count, choose the paper and the trim size, and see the spine width and the full size of your Amazon KDP paperback cover — with bleed, in inches, millimeters and pixels at 300 dpi.
Always look at your final files in KDP's own cover calculator and previewer before you publish: KDP sometimes changes its numbers.
How the KDP spine width is calculated
The spine is the thickness of all your pages: page count × the thickness of one page.
- White paper, black ink: 0.002252 inch per page (100 pages = a 0.225 inch spine)
- Cream paper, black ink: 0.0025 inch per page (100 pages = 0.25 inch)
- White paper, standard color: 0.002252 inch per page
- White paper, premium color: 0.002347 inch per page
The full cover is bleed + back + spine + front + bleed wide, and bleed + height + bleed tall, with a 0.125 inch bleed on each outer edge. For an 8.5 × 11 book of 100 white pages: 0.125 + 8.5 + 0.2252 + 8.5 + 0.125 = 17.475 × 11.25 inches.
Make the whole cover, not only the numbers
GizmoBloom's KDP kit uses these same numbers to make your cover PDF — back, spine and front at the exact size, with bleed and the white box where KDP prints the barcode — plus the interior PDF and the listing.
- Coloring books, activity books and puzzle books made in the app
- 8.5 × 11, 8.5 × 8.5, 8 × 10 and 6 × 9 inches, each as its own paperback
- Spine text from 80 pages, and the printing cost and royalty for your price
Questions about KDP covers
How wide is the spine of a 100-page KDP book?
On white paper with black ink, 100 × 0.002252 = about 0.225 inch (5.7 mm). On cream paper, 0.25 inch (6.4 mm).
When can I put text on the spine?
KDP allows spine text from 80 pages. Thinner books should leave the spine blank.
What is the KDP cover size for an 8.5 × 11 book?
Twice 8.5 inches, plus the spine, plus 0.125 inch of bleed on each side for the width; 11.25 inches for the height. The calculator above does it for your page count.
What is the minimum page count on KDP?
24 pages for paperbacks (72 pages with standard color ink).
What pixel size should my cover be?
The cover size in inches × 300 dots per inch. The calculator shows it for your book.
Make your KDP book and its cover free
Try every feature for 3 days, no card needed. Files made during the trial carry a small SAMPLE mark.